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stmmac: fix a filter problem after resuming.
[linux/fpc-iii.git] / fs / proc / array.c
blobd73291f5f0fcbfb0cd2cff2bb1b628a72f754f6e
1 /*
2 * linux/fs/proc/array.c
3 *
4 * Copyright (C) 1992 by Linus Torvalds
5 * based on ideas by Darren Senn
6 *
7 * Fixes:
8 * Michael. K. Johnson: stat,statm extensions.
9 * <johnsonm@stolaf.edu>
10 *
11 * Pauline Middelink : Made cmdline,envline only break at '\0's, to
12 * make sure SET_PROCTITLE works. Also removed
13 * bad '!' which forced address recalculation for
14 * EVERY character on the current page.
15 * <middelin@polyware.iaf.nl>
16 *
17 * Danny ter Haar : added cpuinfo
18 * <dth@cistron.nl>
19 *
20 * Alessandro Rubini : profile extension.
21 * <rubini@ipvvis.unipv.it>
22 *
23 * Jeff Tranter : added BogoMips field to cpuinfo
24 * <Jeff_Tranter@Mitel.COM>
25 *
26 * Bruno Haible : remove 4K limit for the maps file
27 * <haible@ma2s2.mathematik.uni-karlsruhe.de>
28 *
29 * Yves Arrouye : remove removal of trailing spaces in get_array.
30 * <Yves.Arrouye@marin.fdn.fr>
31 *
32 * Jerome Forissier : added per-CPU time information to /proc/stat
33 * and /proc/<pid>/cpu extension
34 * <forissier@isia.cma.fr>
35 * - Incorporation and non-SMP safe operation
36 * of forissier patch in 2.1.78 by
37 * Hans Marcus <crowbar@concepts.nl>
38 *
39 * aeb@cwi.nl : /proc/partitions
40 *
41 *
42 * Alan Cox : security fixes.
43 * <alan@lxorguk.ukuu.org.uk>
44 *
45 * Al Viro : safe handling of mm_struct
46 *
47 * Gerhard Wichert : added BIGMEM support
48 * Siemens AG <Gerhard.Wichert@pdb.siemens.de>
49 *
50 * Al Viro & Jeff Garzik : moved most of the thing into base.c and
51 * : proc_misc.c. The rest may eventually go into
52 * : base.c too.
53 */
54
55 #include <linux/types.h>
56 #include <linux/errno.h>
57 #include <linux/time.h>
58 #include <linux/kernel.h>
59 #include <linux/kernel_stat.h>
60 #include <linux/tty.h>
61 #include <linux/string.h>
62 #include <linux/mman.h>
63 #include <linux/proc_fs.h>
64 #include <linux/ioport.h>
65 #include <linux/uaccess.h>
66 #include <linux/io.h>
67 #include <linux/mm.h>
68 #include <linux/hugetlb.h>
69 #include <linux/pagemap.h>
70 #include <linux/swap.h>
71 #include <linux/smp.h>
72 #include <linux/signal.h>
73 #include <linux/highmem.h>
74 #include <linux/file.h>
75 #include <linux/fdtable.h>
76 #include <linux/times.h>
77 #include <linux/cpuset.h>
78 #include <linux/rcupdate.h>
79 #include <linux/delayacct.h>
80 #include <linux/seq_file.h>
81 #include <linux/pid_namespace.h>
82 #include <linux/ptrace.h>
83 #include <linux/tracehook.h>
84 #include <linux/string_helpers.h>
85 #include <linux/user_namespace.h>
86
87 #include <asm/pgtable.h>
88 #include <asm/processor.h>
89 #include "internal.h"
90
91 static inline void task_name(struct seq_file *m, struct task_struct *p)
92 {
93 char *buf;
94 size_t size;
95 char tcomm[sizeof(p->comm)];
96 int ret;
97
98 get_task_comm(tcomm, p);
99
100 seq_puts(m, "Name:\t");
101
102 size = seq_get_buf(m, &buf);
103 ret = string_escape_str(tcomm, buf, size, ESCAPE_SPACE | ESCAPE_SPECIAL, "\n\\");
104 seq_commit(m, ret < size ? ret : -1);
105
106 seq_putc(m, '\n');
107 }
108
109 /*
110 * The task state array is a strange "bitmap" of
111 * reasons to sleep. Thus "running" is zero, and
112 * you can test for combinations of others with
113 * simple bit tests.
114 */
115 static const char * const task_state_array[] = {
116 "R (running)", /* 0 */
117 "S (sleeping)", /* 1 */
118 "D (disk sleep)", /* 2 */
119 "T (stopped)", /* 4 */
120 "t (tracing stop)", /* 8 */
121 "X (dead)", /* 16 */
122 "Z (zombie)", /* 32 */
123 };
124
125 static inline const char *get_task_state(struct task_struct *tsk)
126 {
127 unsigned int state = (tsk->state | tsk->exit_state) & TASK_REPORT;
128
129 /*
130 * Parked tasks do not run; they sit in __kthread_parkme().
131 * Without this check, we would report them as running, which is
132 * clearly wrong, so we report them as sleeping instead.
133 */
134 if (tsk->state == TASK_PARKED)
135 state = TASK_INTERRUPTIBLE;
136
137 BUILD_BUG_ON(1 + ilog2(TASK_REPORT) != ARRAY_SIZE(task_state_array)-1);
138
139 return task_state_array[fls(state)];
140 }
141
142 static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
143 struct pid *pid, struct task_struct *p)
144 {
145 struct user_namespace *user_ns = seq_user_ns(m);
146 struct group_info *group_info;
147 int g;
148 struct task_struct *tracer;
149 const struct cred *cred;
150 pid_t ppid, tpid = 0, tgid, ngid;
151 unsigned int max_fds = 0;
152
153 rcu_read_lock();
154 ppid = pid_alive(p) ?
155 task_tgid_nr_ns(rcu_dereference(p->real_parent), ns) : 0;
156
157 tracer = ptrace_parent(p);
158 if (tracer)
159 tpid = task_pid_nr_ns(tracer, ns);
160
161 tgid = task_tgid_nr_ns(p, ns);
162 ngid = task_numa_group_id(p);
163 cred = get_task_cred(p);
164
165 task_lock(p);
166 if (p->files)
167 max_fds = files_fdtable(p->files)->max_fds;
168 task_unlock(p);
169 rcu_read_unlock();
170
171 seq_printf(m,
172 "State:\t%s\n"
173 "Tgid:\t%d\n"
174 "Ngid:\t%d\n"
175 "Pid:\t%d\n"
176 "PPid:\t%d\n"
177 "TracerPid:\t%d\n"
178 "Uid:\t%d\t%d\t%d\t%d\n"
179 "Gid:\t%d\t%d\t%d\t%d\n"
180 "FDSize:\t%d\nGroups:\t",
181 get_task_state(p),
182 tgid, ngid, pid_nr_ns(pid, ns), ppid, tpid,
183 from_kuid_munged(user_ns, cred->uid),
184 from_kuid_munged(user_ns, cred->euid),
185 from_kuid_munged(user_ns, cred->suid),
186 from_kuid_munged(user_ns, cred->fsuid),
187 from_kgid_munged(user_ns, cred->gid),
188 from_kgid_munged(user_ns, cred->egid),
189 from_kgid_munged(user_ns, cred->sgid),
190 from_kgid_munged(user_ns, cred->fsgid),
191 max_fds);
192
193 group_info = cred->group_info;
194 for (g = 0; g < group_info->ngroups; g++)
195 seq_printf(m, "%d ",
196 from_kgid_munged(user_ns, GROUP_AT(group_info, g)));
197 put_cred(cred);
198
199 #ifdef CONFIG_PID_NS
200 seq_puts(m, "\nNStgid:");
201 for (g = ns->level; g <= pid->level; g++)
202 seq_printf(m, "\t%d",
203 task_tgid_nr_ns(p, pid->numbers[g].ns));
204 seq_puts(m, "\nNSpid:");
205 for (g = ns->level; g <= pid->level; g++)
206 seq_printf(m, "\t%d",
207 task_pid_nr_ns(p, pid->numbers[g].ns));
208 seq_puts(m, "\nNSpgid:");
209 for (g = ns->level; g <= pid->level; g++)
210 seq_printf(m, "\t%d",
211 task_pgrp_nr_ns(p, pid->numbers[g].ns));
212 seq_puts(m, "\nNSsid:");
213 for (g = ns->level; g <= pid->level; g++)
214 seq_printf(m, "\t%d",
215 task_session_nr_ns(p, pid->numbers[g].ns));
216 #endif
217 seq_putc(m, '\n');
218 }
219
220 void render_sigset_t(struct seq_file *m, const char *header,
221 sigset_t *set)
222 {
223 int i;
224
225 seq_puts(m, header);
226
227 i = _NSIG;
228 do {
229 int x = 0;
230
231 i -= 4;
232 if (sigismember(set, i+1)) x |= 1;
233 if (sigismember(set, i+2)) x |= 2;
234 if (sigismember(set, i+3)) x |= 4;
235 if (sigismember(set, i+4)) x |= 8;
236 seq_printf(m, "%x", x);
237 } while (i >= 4);
238
239 seq_putc(m, '\n');
240 }
241
242 static void collect_sigign_sigcatch(struct task_struct *p, sigset_t *ign,
243 sigset_t *catch)
244 {
245 struct k_sigaction *k;
246 int i;
247
248 k = p->sighand->action;
249 for (i = 1; i <= _NSIG; ++i, ++k) {
250 if (k->sa.sa_handler == SIG_IGN)
251 sigaddset(ign, i);
252 else if (k->sa.sa_handler != SIG_DFL)
253 sigaddset(catch, i);
254 }
255 }
256
257 static inline void task_sig(struct seq_file *m, struct task_struct *p)
258 {
259 unsigned long flags;
260 sigset_t pending, shpending, blocked, ignored, caught;
261 int num_threads = 0;
262 unsigned long qsize = 0;
263 unsigned long qlim = 0;
264
265 sigemptyset(&pending);
266 sigemptyset(&shpending);
267 sigemptyset(&blocked);
268 sigemptyset(&ignored);
269 sigemptyset(&caught);
270
271 if (lock_task_sighand(p, &flags)) {
272 pending = p->pending.signal;
273 shpending = p->signal->shared_pending.signal;
274 blocked = p->blocked;
275 collect_sigign_sigcatch(p, &ignored, &caught);
276 num_threads = get_nr_threads(p);
277 rcu_read_lock(); /* FIXME: is this correct? */
278 qsize = atomic_read(&__task_cred(p)->user->sigpending);
279 rcu_read_unlock();
280 qlim = task_rlimit(p, RLIMIT_SIGPENDING);
281 unlock_task_sighand(p, &flags);
282 }
283
284 seq_printf(m, "Threads:\t%d\n", num_threads);
285 seq_printf(m, "SigQ:\t%lu/%lu\n", qsize, qlim);
286
287 /* render them all */
288 render_sigset_t(m, "SigPnd:\t", &pending);
289 render_sigset_t(m, "ShdPnd:\t", &shpending);
290 render_sigset_t(m, "SigBlk:\t", &blocked);
291 render_sigset_t(m, "SigIgn:\t", &ignored);
292 render_sigset_t(m, "SigCgt:\t", &caught);
293 }
294
295 static void render_cap_t(struct seq_file *m, const char *header,
296 kernel_cap_t *a)
297 {
298 unsigned __capi;
299
300 seq_puts(m, header);
301 CAP_FOR_EACH_U32(__capi) {
302 seq_printf(m, "%08x",
303 a->cap[CAP_LAST_U32 - __capi]);
304 }
305 seq_putc(m, '\n');
306 }
307
308 static inline void task_cap(struct seq_file *m, struct task_struct *p)
309 {
310 const struct cred *cred;
311 kernel_cap_t cap_inheritable, cap_permitted, cap_effective,
312 cap_bset, cap_ambient;
313
314 rcu_read_lock();
315 cred = __task_cred(p);
316 cap_inheritable = cred->cap_inheritable;
317 cap_permitted = cred->cap_permitted;
318 cap_effective = cred->cap_effective;
319 cap_bset = cred->cap_bset;
320 cap_ambient = cred->cap_ambient;
321 rcu_read_unlock();
322
323 render_cap_t(m, "CapInh:\t", &cap_inheritable);
324 render_cap_t(m, "CapPrm:\t", &cap_permitted);
325 render_cap_t(m, "CapEff:\t", &cap_effective);
326 render_cap_t(m, "CapBnd:\t", &cap_bset);
327 render_cap_t(m, "CapAmb:\t", &cap_ambient);
328 }
329
330 static inline void task_seccomp(struct seq_file *m, struct task_struct *p)
331 {
332 #ifdef CONFIG_SECCOMP
333 seq_printf(m, "Seccomp:\t%d\n", p->seccomp.mode);
334 #endif
335 }
336
337 static inline void task_context_switch_counts(struct seq_file *m,
338 struct task_struct *p)
339 {
340 seq_printf(m, "voluntary_ctxt_switches:\t%lu\n"
341 "nonvoluntary_ctxt_switches:\t%lu\n",
342 p->nvcsw,
343 p->nivcsw);
344 }
345
346 static void task_cpus_allowed(struct seq_file *m, struct task_struct *task)
347 {
348 seq_printf(m, "Cpus_allowed:\t%*pb\n",
349 cpumask_pr_args(&task->cpus_allowed));
350 seq_printf(m, "Cpus_allowed_list:\t%*pbl\n",
351 cpumask_pr_args(&task->cpus_allowed));
352 }
353
354 int proc_pid_status(struct seq_file *m, struct pid_namespace *ns,
355 struct pid *pid, struct task_struct *task)
356 {
357 struct mm_struct *mm = get_task_mm(task);
358
359 task_name(m, task);
360 task_state(m, ns, pid, task);
361
362 if (mm) {
363 task_mem(m, mm);
364 mmput(mm);
365 }
366 task_sig(m, task);
367 task_cap(m, task);
368 task_seccomp(m, task);
369 task_cpus_allowed(m, task);
370 cpuset_task_status_allowed(m, task);
371 task_context_switch_counts(m, task);
372 return 0;
373 }
374
375 static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
376 struct pid *pid, struct task_struct *task, int whole)
377 {
378 unsigned long vsize, eip, esp, wchan = 0;
379 int priority, nice;
380 int tty_pgrp = -1, tty_nr = 0;
381 sigset_t sigign, sigcatch;
382 char state;
383 pid_t ppid = 0, pgid = -1, sid = -1;
384 int num_threads = 0;
385 int permitted;
386 struct mm_struct *mm;
387 unsigned long long start_time;
388 unsigned long cmin_flt = 0, cmaj_flt = 0;
389 unsigned long min_flt = 0, maj_flt = 0;
390 cputime_t cutime, cstime, utime, stime;
391 cputime_t cgtime, gtime;
392 unsigned long rsslim = 0;
393 char tcomm[sizeof(task->comm)];
394 unsigned long flags;
395
396 state = *get_task_state(task);
397 vsize = eip = esp = 0;
398 permitted = ptrace_may_access(task, PTRACE_MODE_READ | PTRACE_MODE_NOAUDIT);
399 mm = get_task_mm(task);
400 if (mm) {
401 vsize = task_vsize(mm);
402 if (permitted) {
403 eip = KSTK_EIP(task);
404 esp = KSTK_ESP(task);
405 }
406 }
407
408 get_task_comm(tcomm, task);
409
410 sigemptyset(&sigign);
411 sigemptyset(&sigcatch);
412 cutime = cstime = utime = stime = 0;
413 cgtime = gtime = 0;
414
415 if (lock_task_sighand(task, &flags)) {
416 struct signal_struct *sig = task->signal;
417
418 if (sig->tty) {
419 struct pid *pgrp = tty_get_pgrp(sig->tty);
420 tty_pgrp = pid_nr_ns(pgrp, ns);
421 put_pid(pgrp);
422 tty_nr = new_encode_dev(tty_devnum(sig->tty));
423 }
424
425 num_threads = get_nr_threads(task);
426 collect_sigign_sigcatch(task, &sigign, &sigcatch);
427
428 cmin_flt = sig->cmin_flt;
429 cmaj_flt = sig->cmaj_flt;
430 cutime = sig->cutime;
431 cstime = sig->cstime;
432 cgtime = sig->cgtime;
433 rsslim = ACCESS_ONCE(sig->rlim[RLIMIT_RSS].rlim_cur);
434
435 /* add up live thread stats at the group level */
436 if (whole) {
437 struct task_struct *t = task;
438 do {
439 min_flt += t->min_flt;
440 maj_flt += t->maj_flt;
441 gtime += task_gtime(t);
442 } while_each_thread(task, t);
443
444 min_flt += sig->min_flt;
445 maj_flt += sig->maj_flt;
446 thread_group_cputime_adjusted(task, &utime, &stime);
447 gtime += sig->gtime;
448 }
449
450 sid = task_session_nr_ns(task, ns);
451 ppid = task_tgid_nr_ns(task->real_parent, ns);
452 pgid = task_pgrp_nr_ns(task, ns);
453
454 unlock_task_sighand(task, &flags);
455 }
456
457 if (permitted && (!whole || num_threads < 2))
458 wchan = get_wchan(task);
459 if (!whole) {
460 min_flt = task->min_flt;
461 maj_flt = task->maj_flt;
462 task_cputime_adjusted(task, &utime, &stime);
463 gtime = task_gtime(task);
464 }
465
466 /* scale priority and nice values from timeslices to -20..20 */
467 /* to make it look like a "normal" Unix priority/nice value */
468 priority = task_prio(task);
469 nice = task_nice(task);
470
471 /* convert nsec -> ticks */
472 start_time = nsec_to_clock_t(task->real_start_time);
473
474 seq_printf(m, "%d (%s) %c", pid_nr_ns(pid, ns), tcomm, state);
475 seq_put_decimal_ll(m, ' ', ppid);
476 seq_put_decimal_ll(m, ' ', pgid);
477 seq_put_decimal_ll(m, ' ', sid);
478 seq_put_decimal_ll(m, ' ', tty_nr);
479 seq_put_decimal_ll(m, ' ', tty_pgrp);
480 seq_put_decimal_ull(m, ' ', task->flags);
481 seq_put_decimal_ull(m, ' ', min_flt);
482 seq_put_decimal_ull(m, ' ', cmin_flt);
483 seq_put_decimal_ull(m, ' ', maj_flt);
484 seq_put_decimal_ull(m, ' ', cmaj_flt);
485 seq_put_decimal_ull(m, ' ', cputime_to_clock_t(utime));
486 seq_put_decimal_ull(m, ' ', cputime_to_clock_t(stime));
487 seq_put_decimal_ll(m, ' ', cputime_to_clock_t(cutime));
488 seq_put_decimal_ll(m, ' ', cputime_to_clock_t(cstime));
489 seq_put_decimal_ll(m, ' ', priority);
490 seq_put_decimal_ll(m, ' ', nice);
491 seq_put_decimal_ll(m, ' ', num_threads);
492 seq_put_decimal_ull(m, ' ', 0);
493 seq_put_decimal_ull(m, ' ', start_time);
494 seq_put_decimal_ull(m, ' ', vsize);
495 seq_put_decimal_ull(m, ' ', mm ? get_mm_rss(mm) : 0);
496 seq_put_decimal_ull(m, ' ', rsslim);
497 seq_put_decimal_ull(m, ' ', mm ? (permitted ? mm->start_code : 1) : 0);
498 seq_put_decimal_ull(m, ' ', mm ? (permitted ? mm->end_code : 1) : 0);
499 seq_put_decimal_ull(m, ' ', (permitted && mm) ? mm->start_stack : 0);
500 seq_put_decimal_ull(m, ' ', esp);
501 seq_put_decimal_ull(m, ' ', eip);
502 /* The signal information here is obsolete.
503 * It must be decimal for Linux 2.0 compatibility.
504 * Use /proc/#/status for real-time signals.
505 */
506 seq_put_decimal_ull(m, ' ', task->pending.signal.sig[0] & 0x7fffffffUL);
507 seq_put_decimal_ull(m, ' ', task->blocked.sig[0] & 0x7fffffffUL);
508 seq_put_decimal_ull(m, ' ', sigign.sig[0] & 0x7fffffffUL);
509 seq_put_decimal_ull(m, ' ', sigcatch.sig[0] & 0x7fffffffUL);
510
511 /*
512 * We used to output the absolute kernel address, but that's an
513 * information leak - so instead we show a 0/1 flag here, to signal
514 * to user-space whether there's a wchan field in /proc/PID/wchan.
515 *
516 * This works with older implementations of procps as well.
517 */
518 if (wchan)
519 seq_puts(m, " 1");
520 else
521 seq_puts(m, " 0");
522
523 seq_put_decimal_ull(m, ' ', 0);
524 seq_put_decimal_ull(m, ' ', 0);
525 seq_put_decimal_ll(m, ' ', task->exit_signal);
526 seq_put_decimal_ll(m, ' ', task_cpu(task));
527 seq_put_decimal_ull(m, ' ', task->rt_priority);
528 seq_put_decimal_ull(m, ' ', task->policy);
529 seq_put_decimal_ull(m, ' ', delayacct_blkio_ticks(task));
530 seq_put_decimal_ull(m, ' ', cputime_to_clock_t(gtime));
531 seq_put_decimal_ll(m, ' ', cputime_to_clock_t(cgtime));
532
533 if (mm && permitted) {
534 seq_put_decimal_ull(m, ' ', mm->start_data);
535 seq_put_decimal_ull(m, ' ', mm->end_data);
536 seq_put_decimal_ull(m, ' ', mm->start_brk);
537 seq_put_decimal_ull(m, ' ', mm->arg_start);
538 seq_put_decimal_ull(m, ' ', mm->arg_end);
539 seq_put_decimal_ull(m, ' ', mm->env_start);
540 seq_put_decimal_ull(m, ' ', mm->env_end);
541 } else
542 seq_printf(m, " 0 0 0 0 0 0 0");
543
544 if (permitted)
545 seq_put_decimal_ll(m, ' ', task->exit_code);
546 else
547 seq_put_decimal_ll(m, ' ', 0);
548
549 seq_putc(m, '\n');
550 if (mm)
551 mmput(mm);
552 return 0;
553 }
554
555 int proc_tid_stat(struct seq_file *m, struct pid_namespace *ns,
556 struct pid *pid, struct task_struct *task)
557 {
558 return do_task_stat(m, ns, pid, task, 0);
559 }
560
561 int proc_tgid_stat(struct seq_file *m, struct pid_namespace *ns,
562 struct pid *pid, struct task_struct *task)
563 {
564 return do_task_stat(m, ns, pid, task, 1);
565 }
566
567 int proc_pid_statm(struct seq_file *m, struct pid_namespace *ns,
568 struct pid *pid, struct task_struct *task)
569 {
570 unsigned long size = 0, resident = 0, shared = 0, text = 0, data = 0;
571 struct mm_struct *mm = get_task_mm(task);
572
573 if (mm) {
574 size = task_statm(mm, &shared, &text, &data, &resident);
575 mmput(mm);
576 }
577 /*
578 * For quick read, open code by putting numbers directly
579 * expected format is
580 * seq_printf(m, "%lu %lu %lu %lu 0 %lu 0\n",
581 * size, resident, shared, text, data);
582 */
583 seq_put_decimal_ull(m, 0, size);
584 seq_put_decimal_ull(m, ' ', resident);
585 seq_put_decimal_ull(m, ' ', shared);
586 seq_put_decimal_ull(m, ' ', text);
587 seq_put_decimal_ull(m, ' ', 0);
588 seq_put_decimal_ull(m, ' ', data);
589 seq_put_decimal_ull(m, ' ', 0);
590 seq_putc(m, '\n');
591
592 return 0;
593 }
594
595 #ifdef CONFIG_PROC_CHILDREN
596 static struct pid *
597 get_children_pid(struct inode *inode, struct pid *pid_prev, loff_t pos)
598 {
599 struct task_struct *start, *task;
600 struct pid *pid = NULL;
601
602 read_lock(&tasklist_lock);
603
604 start = pid_task(proc_pid(inode), PIDTYPE_PID);
605 if (!start)
606 goto out;
607
608 /*
609 * Lets try to continue searching first, this gives
610 * us significant speedup on children-rich processes.
611 */
612 if (pid_prev) {
613 task = pid_task(pid_prev, PIDTYPE_PID);
614 if (task && task->real_parent == start &&
615 !(list_empty(&task->sibling))) {
616 if (list_is_last(&task->sibling, &start->children))
617 goto out;
618 task = list_first_entry(&task->sibling,
619 struct task_struct, sibling);
620 pid = get_pid(task_pid(task));
621 goto out;
622 }
623 }
624
625 /*
626 * Slow search case.
627 *
628 * We might miss some children here if children
629 * are exited while we were not holding the lock,
630 * but it was never promised to be accurate that
631 * much.
632 *
633 * "Just suppose that the parent sleeps, but N children
634 * exit after we printed their tids. Now the slow paths
635 * skips N extra children, we miss N tasks." (c)
636 *
637 * So one need to stop or freeze the leader and all
638 * its children to get a precise result.
639 */
640 list_for_each_entry(task, &start->children, sibling) {
641 if (pos-- == 0) {
642 pid = get_pid(task_pid(task));
643 break;
644 }
645 }
646
647 out:
648 read_unlock(&tasklist_lock);
649 return pid;
650 }
651
652 static int children_seq_show(struct seq_file *seq, void *v)
653 {
654 struct inode *inode = seq->private;
655 pid_t pid;
656
657 pid = pid_nr_ns(v, inode->i_sb->s_fs_info);
658 seq_printf(seq, "%d ", pid);
659
660 return 0;
661 }
662
663 static void *children_seq_start(struct seq_file *seq, loff_t *pos)
664 {
665 return get_children_pid(seq->private, NULL, *pos);
666 }
667
668 static void *children_seq_next(struct seq_file *seq, void *v, loff_t *pos)
669 {
670 struct pid *pid;
671
672 pid = get_children_pid(seq->private, v, *pos + 1);
673 put_pid(v);
674
675 ++*pos;
676 return pid;
677 }
678
679 static void children_seq_stop(struct seq_file *seq, void *v)
680 {
681 put_pid(v);
682 }
683
684 static const struct seq_operations children_seq_ops = {
685 .start = children_seq_start,
686 .next = children_seq_next,
687 .stop = children_seq_stop,
688 .show = children_seq_show,
689 };
690
691 static int children_seq_open(struct inode *inode, struct file *file)
692 {
693 struct seq_file *m;
694 int ret;
695
696 ret = seq_open(file, &children_seq_ops);
697 if (ret)
698 return ret;
699
700 m = file->private_data;
701 m->private = inode;
702
703 return ret;
704 }
705
706 int children_seq_release(struct inode *inode, struct file *file)
707 {
708 seq_release(inode, file);
709 return 0;
710 }
711
712 const struct file_operations proc_tid_children_operations = {
713 .open = children_seq_open,
714 .read = seq_read,
715 .llseek = seq_lseek,
716 .release = children_seq_release,
717 };
718 #endif /* CONFIG_PROC_CHILDREN */
Linux with added FPC-III support